Certain known ski boots of this type generally have a rigid shell base topped by a shank made of two parts, a collar and 2 spoiler, at least one of the two parts being movable with respect to the other to allow the introduction of the skier's foot when the boot is being put on. For these boots, the closing of the boot on the foot and the skier's leg is most often achieved by bringing the spoiler towards the collar through the use of a tension application device comprised of at least one flexible brace under the control of a foot support system and a leg base support system. In these boots, due to the use of at least one flexible brace, the active length of this flexible brace is determinative for the stresses of closing and tightening, and it is thus necessary to connect to the tension application device a means of adjusting said active length of the brace.
As an example, known boots of this type are described in European Patent Application No. 0053340; they comprise a system for supporting the foot and a system for supporting the base of the leg, which are each controlled by a single tension application device through the intermediary of a flexible brace, one part of which is connected in a position-controllable manner on said device; thus, by changing the position of said part of one or both of the braces on the corresponding tension application device, the active length of these and thus their tension is equally modified. As will be noted, each tension application device thus allows adjustment of the length of the flexible brace which is dependent on it and the tension applied to the corresponding support system. This differentiation is desirable because the support of the base of the leg must be relatively more firm than the support on the foot. However, separating the controls for support of the foot and of the base of the leg makes the closing and adjustment of the boot inconvenient and complex to execute; actually, it is necessary to successively adjust the length of one brace, then the other, by trial and error, by placing the respective tension application devices in unlocked position, then by bringing them back into locked position to control the tension stress resulting from the adjustment made.
Other boots are equipped with tension application devices comprised of winders, allowing, in a single maneuver, the modification of the active length of a brace and its tension. These devices are in the form of a spool, whose rotating movement is effected by action on an external reel.
Due to the relatively small size of these spools, which must be associated with the boots, the rotation stress which can be applied manually is incompatible with that of the tension to be obtained on the brace for an optimum support of the foot, in particular, with regard to women and children.
Thus, certain manufacturers have planned to provide such winding devices with a spool equipped with a step-down wheel gear. With such an assembly, a certain number of rotations of the spool must occur to wind up a relatively small portion of the brace. Thus, to arrive at bringing the spoiler and the collar together with such a device, when the boot is put on, it is necessary to execute a great number of rotations, with the consequent length of brace to wind up.
In another instance, for this type of boot, two braces have been provided which could be coupled on the spool whose rotating movement then causes the winding or unwinding of the two braces simultaneously and in the same lengths. Such winding devices also turned out to be unsuitable for the single controls for tightening of the braces which control at once the internal foot bracing system and the leg support system. In fact, in this case, the winding of the braces and their tension are not differentiated according to each of the said support systems.
However, the leg base support system in particular requires a high degree of availability of the length of the brace, to allow the relative distancing of the spoiler from the collar and thus to allow the boot to be put on, contrary to the foot support system.